Microdrive: High Capacity Storage for the Handheld Revolution

Transcription

1 Microdrive: High Capacity Storage for the Handheld Revolution IBM Almaden Research Center San Jose, CA IBM Mobile Storage Development Fujisawa, Japan IBM Storage Systems Division San Jose, CA

2 Recent History June 1999 Gen 1 Product Autumn 1998 Technology Introduction June 2000 Gen 2 Product

3 CompactFlash Type II Form Factor 42.8 mm 36.4 mm CompactFlash type I already established as leading storage form factor for cameras, handheld PCs 5 mm Type II (introduced by CFA 12/98) is identical to Type I except height increased from 3.3 mm to 5 mm Microdrive brings high capacity HDD storage to hand-held devices

4 Microdrive: Selected Specs Specification Dimensions Capacity Disk diameter Areal Density (Gb/sq.in.) Avg Seek Time Data Rate (MB/s) Rotational Speed (RPM) Power Requirements - Spin Up - Read/Write - Idle - Standby Shock: - Non-OP - Operating Weight Interface Gen 1 (340 MB) 42.8 x 36.4 x 5.0 mm 340 / 170 MB 27.4 mm 5.04 (Max) 15ms 3.2 (Max) v, 5.0 v + / - 5% 260mA 300mA 220mA 65mA 1000 G 150 G 16g CF (ATA) Gen 2 (1.0 GB) 42.8 x 36.4 x 5.0 mm 340 / 512 MB/ 1.0 GB 27.4 mm 15.2 (Max) 12ms 4.2 (Max) v, 5.0 v + / - 5% 260mA 250mA 140mA 20mA 1500 G 175 G 16 g CF (ATA)

5 Microdrive Technology

6 Are micromechanics required to make a microdrive? Microdrive project started with goal of using MEMS to make a disk drive... (L.S. Fan)

7 Microdrive: Intelligently Scaled Conventional Design Properly scaled conventional designs turned out to be a cheaper and better approach. MEMS technology is not ready to replace most components yet: bearings (lubrication and life) motors (available torque) expense (too high)

8 Electronics Card RAM CONTROLLER SPIN/ VCM Total card area: 10 cm 2 double sided (most on one side) 6X smaller than 2.5" HDD card, with all the same functions All modules: direct chip attach (no package, no wire bonding) CHANNEL One of the most compact electronics cards in industry today card thickness: 0.4 mm (4 layer) component height: 0.9 mm cm scale

9 Spindle Motor STATOR COIL 2 X 5 mm BALL BEARINGS ROTOR MAGNET 18.6 mm INNER ROTOR DESIGN rotating mass dominated by spindle rotor, not disk (unlike most drives) oversize (not scaled) bearings (for manufacturability, shock resistance) reduced mass (increased resistance to linear shock) reduced rotational inertia (spin up time ~ 0.5 sec) reduced tilt inertia (increased resistance to rotational shock) increased Kt (more room for windings) 12-pole 9-slot design; K t = Nm/A future: fluid dynamic bearing (higher track dens, better acoustics, better shock)

10 Actuator transfer function clean out to ~ 7 khz similar to moving-suspension secondary actuators in larger drives may achieve dual-stage performance without second stage 0 db khz Frequency 10 khz 127 turn coil overmolded plastic carriage integrated lead suspension K t ~ Nm/A I ~ 0.1 g cm 2

11 Air Bearing Can a conventional ABS work in a microdrive? ILS suspension with pico slider Requirements: m/sec linear velocity sub 1 microinch FH good tolerances nano ABS from early prototype pico subambient pad ABS used in product

12 Load/Unload SPINDLE TORQUE TOO LOW FOR CONTACT START-STOP limited coil winding space CompactFlash requires 3.3 V operation, limits K t oversize bearing (not scaled) results in disproportionately high drag OTHER ADVANTAGES OF L/UL increased nonoperating shock resistance (eliminates head slap) elimination of stiction/wear failures reduced power consumption (unlimited start/stops for aggressive power savings) increased areal density (smooth disk for low noise, low flying height) ease of assembly (no head merge operation)

13 Design Considerations for SHOCK Microdrive has 1500 G nonop shock spec (industry best) For "throw it against the wall" durability: Contributing factors: Load/Unload (eliminate head slap) Oversize spindle and actuator bearings (higher brinaling threshold) Suspension limiters (prevent gimbal damage, slider-slider contact) Inertia latch (keep actuator reliably parked) "True Track" super-harmonic servo (allows for some disk slip) Compact shock mounting system from Edapting Solutions

14 Microdrive Applications

15 Microdrive Opportunity Information Appliances removable storage subnotebook PCs PC cards printers communications: PC, cellular, pager routers Microdrive voice recognition MPEG4 video players dictionaries MP3 audio players digital still cameras digital video cameras GPS games Consumer Electronics

16 Potential Host Devices: Volume Projections Digital Audio Wearable PC Automotive / GPS Units (Millions) Smart Phones Video Cameras HPCs / PDAs Still Cameras Notebook PCs even a small percentage penetration into these markets represents significant volume

17 Digital Cameras most popular use of Microdrive image capacity for 1 GB: Casio QV3000 camera (3.3 Mpel) compressed: x 1530 pel x 768 pel uncompressed: x 1530 pel (Canon digital camera) uncompressed images: superior quality better for subsequent editing 10 MB per 3.3 MP only practical with Microdrive

18 MP3 Audio Players MPEG-1 audio layer 3 compressed audio (16X smaller than CD) data rate 128 kb/sec (16 KB/sec, ~1 MB/min) competition uses solid state flash memory (typically MB) flash is not a very good solution (too expensive) Microdrive-based MP3 Player designed by e.digital (coming to market soon) high capacity of Microdrive is ideal

19 Mythical Problem: Microdrive Power Consumption flash memory card MP3 player electronics Total V V V IBM Microdrive MP3 player electronics Total V V V 3.6 X more current There is a better way... more than 5X shorter battery life

20 Solution: Add a Data Buffer MP3 data rate: 16 KB/sec Microdrive minimum sustained data rate: 1.8 MB/sec Microdrive is > 100X too fast! IBM Microdrive buffer RAM 1 MB MP3 player electronics V 5% duty cycle 15 ma average V V Microdrive consumes only 15% of total power negligible effect on battery life vs. flash memory hrs battery life with pair of AA batteries

21 Digital Video Players Enterprise to Entertainment MPEG4 Video with 8 MB buffer Data Rate Duty Cycle* Ave. Current 300 kb/s 3.3% 8 ma 1 Mb/s 10% 25 ma 1.6 Mb/s 15% 38 ma Assumptions: 2 MB/sec sustained data rate 2 seconds overhead per buffer cycle Negligible effect on battery life vs flash memory

22 1 inch today => 1 cm tomorrow? 100 Price trends for storage 10 $/MB $/MB flash microdrive 2.5" HDD 3.5" HDD year Microdrive market occupies widening gap between flash and larger HDDs

23 1 inch today => 1 cm tomorrow? 10 $/MB COST ($/MB) flash flash curve Microdrives 2.5" & 3.5" HDDs capacity (MB) HDD curve Fixed costs of HDDs needs to be reduced before further downward scaling in size (Flash scales down better)

24 Microdrive: Summary World's smallest, lightest HDD World's lowest power HDD World's most shock resistant HDD Based on intelligently scaled conventional design Most important applications: digital cameras MP3 audio players MPEG4 video players Achieves excellent battery life in sequential access applications (audio, video)